Research article

N-Methyl-D-aspartic Acid (NMDA) in the nervous system of the amphioxus Branchiostoma lanceolatum

Salvatore D'Aniello¹ , George H Fisher² , Enza Topo³ , Gabriele Ferrandino³ , Jordi Garcia-Fernàndez^{* 1} and Antimo D'Aniello^{* 3}

¹Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona, Spain

²Department of Chemistry, Barry University, Miami Shores, Florida 33161, USA

³Laboratory of Neurobiology, Stazione Zoologica "A. Dohrn", Villa Comunale 1, 80121 Napoli, Italy

author email corresponding author email* Contributed equally

BMC Neuroscience 2007, 8:109doi:10.1186/1471-2202-8-109

Published:	20 December 2007

Abstract

Background

NMDA (N-methyl-D-aspartic acid) is a widely known agonist for a class of glutamate receptors, the NMDA type. Synthetic NMDA elicits very strong activity for the induction of hypothalamic factors and hypophyseal hormones in mammals. Moreover, endogenous NMDA has been found in rat, where it has a role in the induction of GnRH (Gonadotropin Releasing Hormone) in the hypothalamus, and of LH (Luteinizing Hormone) and PRL (Prolactin) in the pituitary gland.

Results

In this study we show evidence for the occurrence of endogenous NMDA in the amphioxus Branchiostoma lanceolatum. A relatively high concentration of NMDA occurs in the nervous system of this species (3.08 ± 0.37 nmol/g tissue in the nerve cord and 10.52 ± 1.41 nmol/g tissue in the cephalic vesicle). As in rat, in amphioxus NMDA is also biosynthesized from D-aspartic acid (D-Asp) by a NMDA synthase (also called D-aspartate methyl transferase).

Conclusion

Given the simplicity of the amphioxus nervous and endocrine systems compared to mammalian, the discovery of NMDA in this protochordate is important to gain insights into the role of endogenous NMDA in the nervous and endocrine systems of metazoans and particularly in the chordate lineage.